Meaning: 1. A camel: an underwater compartment pumped free of water used to raise sunken objects or to work on bridge foundations. 2. A chest or container for ammunition or other explosives. 3. A horse-drawn wagon formerly used to carry ammunition but currently used to carry coffins at military funerals.

Notes: The spelling of today's word is odd because it was borrowed from French rather recently (around 1700) and has retained its French spelling. Remember the silent I and double S when you spell it.

In Play: The shift in meaning of today's Good Word has had an ironic effect on the famous Army song, "The Caissons Go Rolling Along":Over hill, over daleAs we hit the dusty trail, And the caissons go rolling along.This word has always been indirectly associated with death, but today it is almost exclusively used with that reference: "The nation mourned as the caisson bearing the body of President Kennedy passed across our television screens." Of course, should you ever lay a foundation below water level, you will need the other type of caisson: "Architects learned a lot about caisson safety from the building of the Brooklyn Bridge."

Word History: The meanings above are ordered chronologically to show how the sense of today's word wandered from an underwater box to a carriage for a coffin. Caisson "large box" is an augmentative of French caisse "cash box", from which English also gets its word cash. Caisse is the French form of Latin capsa "box, case", a noun derived from capere "to take, hold", whose root also underlies capture and captivate. The original Proto-Indo-European root developed into German haben and English have, since the PIE [k] sound developed into English [h] in initial position and [gh] elsewhere in words. All these words are things that hold or are held. (Today we are beholden to Chris Berry for suggesting we write up this captivating word.)

Of course the first thing I looked up when I got to AD was "camel." After the animal, the second definition was:device used to raise sunken objects, consisting of a hollow structure that is submerged, attached tightly to the object, and pumped free of water. Also called caisson.I had never heard the term "camel" used that way before. With my muddled mind, you can imagine the image that would have arisen on hearing the song. I would have seen a military caravan with horse trailers carrying hump-backed animals!

I learned about the subject firsthand while serving on a nuclear submarine. Some men washed out of sub school when they failed the high pressure air chamber test or bouyant free ascent. I had the unpleasant experience of watching blood oozing from the ears of a fellow testee when his eardrums burst. Just attempting to qualify posed some degree of risk.Caisson workers on the Brooklyn Bridge suffered quite a bit before the phenomenon was completely understood and preventive measures taken.

Move Latin "capsa" to Spanish and I think you get “caja”. Caja means box in Spanish. There is a landmark mesa in South Texas that is called San Cajo. This is a folk rendering of the real name Sin Caja. I could see this mesa from the top of the windmill on our farm. Sin means without. The legend is that a box of gold was emptied into a hole at the base of the mesa. Many people have searched for this fabled treasure. Southwestern writer, J Frank Dobie mentions this "treasure" in his writings, I think in "Coronado's Children". This is quite an excursion from "caisson", but it is where my rambling mind took me. Have I gone down a rabbit hole or been chasing rabbits?

Shipley traces these words to the PIE "kap" meaning to hold or contain.

In Spain, a savings bank (Spanish: caja de ahorros or informally just caja, Catalan: caixa d'estalvis, Galician: caixa de aforros, informally 'caixa', Basque: aurrezki kutxa) is a financial institution which specializes in accepting savings deposits and granting loans. Their original aim was to create the habit of thrift amongst the very poor but they have evolved to compete with and rival commercial banks.

Their trade association is the Spanish Confederation of Savings Banks (Confederación Española de Cajas de Ahorro or CECA)...

One would think savings bank in Spanish would be banco de ahorross instead of caja de ahorros. That is up to the Spanish. I am pretty sure a TexMex speaker would not know what caja de ahorros means since he would be thinking about any kind box. He might think it was a safe you had in your house. I will check with my brother, the final authority on TexMex, about this.